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1. |
The OxyLite: a fibre-optic oxygen sensor. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 627-630
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DOI:10.1259/bjr.72.859.10624317
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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2. |
Evaluation of head examinations produced with a mobile CT unit. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 631-636
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PDF (606KB)
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摘要:
Recent years have seen the development of mobile CT units, designed for use in operating theatres, intensive care units and accident and emergency departments. One such unit is the Tomoscan M (Philips, Utrecht, The Netherlands). It operates with a maximum tube voltage of 130 kV, and a maximum tube current of only 50 mA. This study tested whether acceptable quality CT images of the brain could be produced on the mobile unit with these parameters. 44 consecutive normal head examinations performed on the mobile scanner were compared with 35 examinations from two conventional CT units. Two independent readers scored the examinations for noise and artefact. CT dose index (CTDI) values for the three CT units were obtained in free air as an estimate of patient dose. Differences in artefact score between CT units were generally small, but noise scores were worse when using the Tomoscan M with a 2 s slice time. The lowest CTDI values were obtained with the Somatom DRH (Siemens, Erlangen, Germany) unit and the highest with the SR 7000 (Philips, Utrecht, The Netherlands), with values from Tomoscan M, in all except one case, falling between these values for the protocols used in the study. The measured scattered radiation doses from the Tomoscan M are presented.
DOI:10.1259/bjr.72.859.10624318
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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3. |
Transient splenomegaly in acute pancreatitis. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 637-643
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PDF (708KB)
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摘要:
Serial changes in splenic volume of 25 patients (18 men and seven women; 53.4 +/- 20.8 years old, range 25-83) with acute pancreatitis who underwent CT examinations were retrospectively studied. Abdominal CT was performed within 3 days after the onset and there was at least one follow-up CT examination after this time. The percentage changes of splenic volume in the first (4-30 days) and second (31-100 days) follow-up CT were calculated. Splenic volume increased in the first follow-up CT (mean +/- SD: 197.8 +/- 121.0 cm3) compared with the initial CT (124.8 +/- 70.0; p<0.0001), and then decreased in the second follow-up CT (179.7 +/- 100.7; p<0.002). The average splenic volume increased 65.5 +/- 88.7% (range -10.4-377.4%) between the initial and first follow-up CT examinations. Five of 25 cases (20%) in whom size of spleen increased more than twice had severe acute pancreatitis (p<0.05), complicated pseudocyst requiring surgical drainage (p<0.05), pleural effusion (p<0.01), splenic vein thrombosis or compression (p<0.05) and longer hospital stay (p<0.02) compared with patients with a smaller increase in splenic volume. In conclusion, transient splenomegaly was commonly seen in acute pancreatitis, especially in severe or complicated cases. Congestive splenomegaly caused by obstruction or stenosis of the splenic vein and non-specified acute splenitis were suspected of contributing to the transient splenomegaly.
DOI:10.1259/bjr.72.859.10624319
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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4. |
Cricoid cartilage masquerading as a tumour on thyroid ultrasound. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 644-647
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PDF (584KB)
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摘要:
On ultrasound scanning of the thyroid gland in a sagittal plane, the cricoid cartilage can falsely create the impression of a mass in the gland if the transducer is angled slightly medially. The illusion of a mass is fortified on transverse view if the cricothyroid and inferior pharyngeal constrictor muscles, which lie between the upper pole of the thyroid gland and the cricoid cartilage, are misinterpreted as a solid lesion. The purpose of this study was to describe the ultrasound features of the cricoid cartilage and to determine the frequency in which a pseudolesion is created. In 15 of 26 volunteers the cartilage was seen as a hypoechoic structure surrounded by an anechoic halo and containing foci of calcification, closely resembling a thyroid nodule. In 11 of the subjects, with a mean age of 55 years, the cartilage was heavily calcified, poorly visualized and did not simulate a thyroid lesion. Awareness of the cause and appearance of this pseudolesion should help radiologists avoid a potential pitfall and prevent unnecessary invasive procedures.
DOI:10.1259/bjr.72.859.10624320
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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5. |
Adverse reactions to radiocontrast media in an Indian population. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 648-652
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摘要:
This study was conducted to determine the epidemiological characteristics and clinical presentation of adverse reactions to intravenous radiocontrast media (CM) in patients of Indian origin. 379 of 1798 patients who received either sodium iothalamate or sodium meglumine diatrizoate developed adverse reactions (i.e. 21.08% of patients). The incidence of mild, moderate and severe adverse reactions were 19.47%, 1.33% and 0.28%, respectively. One patient who developed a severe reaction expired. There were no differences in the incidence of adverse reactions according to gender (males 21.2%; females 20.8%; p = 0.907) or age (p = 0.876). The incidence of adverse reactions was significantly higher in patients with a history of previous reactions (45.5%) than in those with no history (20.9%; p = 0.046). The incidence of reactions was also significantly higher in patients with a history of predisposing factors such as bronchial asthma (69.2%) and diabetes mellitus (60.0%) than in those without such a history (20.6%; p = 0). The incidence of adverse reactions in patients who received premedication prior to CM administration because of a history of predisposing factors (21.4%) was not significantly different from that in patients who were not premedicated (21.2%; p = 0.974), a result probably due to inadequate premedication used in the study. The skin was the most commonly affected site of reaction.
DOI:10.1259/bjr.72.859.10624321
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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6. |
A comparison of image reject rates when using film, hard copy computed radiography and soft copy images on picture archiving and communication systems (PACS) workstations. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 653-660
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PDF (83KB)
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摘要:
A comparison has been made of the reject rates of plain images for three separate periods when film, computed radiography (CR) and PACS systems were in operation throughout the Hammersmith Hospital, London. There was a statistically significant reduction in the overall percentage reject rate across all examinations from 9.9% to 8.1% when the hospital changed from using a conventional film based system to a CR system. There was a further reduction in the reject rate to 7.3% when the hospital moved to a hospital-wide PACS system, but this change was not statistically significant. Using estimations of the total number of images used, the percentage reject rates were 6.6% for film, 5.5% for CR and 5.5% for PACS. Thus, if the radiation dose for each image is unchanged, and the same types of images are used for the examination of each body area, a move from conventional film imaging to phosphor plate imaging provides the potential to reduce the patient population dose.
DOI:10.1259/bjr.72.859.10624322
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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7. |
Anomalies in dual energy X-ray absorptiometry measurements of total-body bone mineral during weight change using Lunar, Hologic and Norland instruments. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 661-669
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摘要:
A previous study showed that measurements of total-body bone mineral changes made with a Hologic QDR 1000W were unreliable when the subjects underwent weight change. The study has been extended to dual energy X-ray absorptiometry (DXA) apparatus from other manufacturers. Re-analysis of published results during weight loss using a Lunar DPX showed that they varied with the software used. Using the Extended mode, there was a 1% loss of bone mineral areal density (BMD), but no significant change in bone mineral content (BMC) or bone area (BA) following a weight loss of 16 kg, whereas the use of the Standard mode led to a larger fall of BMC and BMD. Similar findings arose from the consideration of two studies using Norland XR 26 HS absorptiometers. On the other hand, separation of two groups with similar weight changes from the population studied with a Hologic QDR 1000W confirmed that BMC changed directly with weight, but there was an inverse relationship for BMD, owing to an inappropriate change of BA. The use of Hologic Enhanced and Standard software modes led to significant differences in initial readings and measured changes. With each instrument there was a strong correlation between changes in BA and changes in BMC. When 6 kg of lard was wrapped around the limbs of volunteers or a semi-anthropomorphic phantom to simulate weight change, there were spurious increases of measured BMC and BA by about 5% with each instrument. There were no changes of BMD with Lunar, variable results with Norland, but decreases with Hologic. The results observed in vivo could be explained by the effects of fat changes, without there being any real change of bone mineral. Changes of BMD in the skeleton of the phantom were underestimated with all three brands. The anomaly observed with the Hologic QDR 1000W is less apparent with a Lunar DPX or a Norland XR 26, but there are sufficient uncertainties for all total-body measurements during weight change to be treated with suspicion.
DOI:10.1259/bjr.72.859.10624323
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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8. |
Analysis of optical density and contrast in mammograms. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 670-677
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PDF (668KB)
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摘要:
The objective of this project is the development of tools for the UK NHSBSP to assess image quality quantitatively in clinical films, for the purposes of optimizing imaging procedures and audit. As an initial step, 120 mammograms of 46 women on a single day of screening were digitized and analysed to produce indices of optical density (OD) and contrast. Analysis was performed on three regions of interest (ROI): pectoral muscle, main breast and skin edge. Two radiologists independently graded the quality of information in the different parts of each mammogram, and categorized breast type as either "dense", "mixed density" or "fatty". Measurements of contrast and OD generally correlated well with the opinions of the radiologists. For the oblique mammograms, the mean OD in the main breast ranged between films from 1.25 to 2.24 with a mean of 1.69 +/- 0.02. In the craniocaudal mammograms, the mean OD in the main breast ROI ranged from 1.14 to 1.94 with a mean of 1.61 +/- 0.05. The OD for a quality control film of a 40 mm block of PMMA exposed on the same day with this system was 1.53. A contrast index (CI) was calculated for each mammogram as the difference between the points of maximum and minimum OD in the main breast. Mean CI was 1.02 +/- 0.09 for fatty breasts, 1.50 +/- 0.10 for mixed density breasts and 2.05 +/- 0.23 for dense breasts. A review of the radiologist assessments indicated that the main breast was satisfactorily displayed when glandular and fatty tissues were displayed within the OD range 0.8-2.9. An analysis of the dynamic range requirements showed that 17% of films had a dynamic range that lay above that calculated using the suggested OD limits.
DOI:10.1259/bjr.72.859.10624324
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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9. |
Assessing chemotherapy response of squamous cell oesophageal carcinoma with spiral CT. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 678-684
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PDF (195KB)
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摘要:
45 patients with squamous cell carcinoma of the oesophagus were examined prior to, and following, pre-operative chemotherapy by spiral CT. Oesophageal CT was performed following gaseous distention of the oesophagus. TNM stage and perceived resectability on CT before and after chemotherapy were compared and related to surgical resectability and pathological staging. T-stage changed in 26% and N-stage changed in 9% of tumours after chemotherapy. Post-chemotherapy CT predicted pathological T-stage with an accuracy of 88% and N-stage with an accuracy of 84%. Six of 14 tumours considered irresectable on CT pre-chemotherapy were considered resectable on post-chemotherapy CT. Five of these six tumours were resectable at surgery. Post-chemotherapy CT predicted surgical resectability with an accuracy of 88%, the main pitfall being underestimation and overestimation of tracheobronchial invasion. CT prediction of chemotherapy response as judged by change in tumour volume was compared with a quantitative pathological assessment of chemotherapy response. 93% of oesophageal tumours changed volume after chemotherapy with 51% having a volume reduction of>or = 50%. However, no correlation was found between tumour volume reduction on serial CT examinations and either a quantitative pathological assessment of tumour response or patient survival.
DOI:10.1259/bjr.72.859.10624325
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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10. |
Accuracy of alignment in breast irradiation: a retrospective analysis of clinical practice. |
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The British Journal of Radiology,
Volume 72,
Issue 859,
1999,
Page 685-690
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PDF (424KB)
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摘要:
The objective of the study was to determine the accuracy of patient positioning in radiotherapy for breast cancer. Portal images were obtained using a fast electronic megavoltage radiotherapy imaging system in 30 cases of breast cancer. Quantitative analysis of 530 megavolt portal images and comparison with 30 digitized simulation films were performed. Five linear measurements were taken for each simulation and verification film. Central lung distance (CLD) is the distance from the dorsomedial beam edge to the inner thoracic wall in the central plane of the beam. Cranial lung distance (CrLD) is the distance from the dorsomedial beam edge to the inner thoracic wall in the plane of the beam at 4 cm from the central plane. Central beam edge to skin distance (CBESD) is the distance from the skin to the ventrolateral beam edge in the central plane of the beam. The central irradiated width (CIW) is defined as the distance from the dorsomedial beam edge to the skin. The craniocaudal distance (CCD) is defined as the distance from a particular landmark to the caudal field border. Concerning patient position in the field, mean standard deviations of the difference between simulation and treatment images were 3.9 mm for the CLD, 3.2 mm at +4 cm, 3.6 mm for the CIW, 3.3 mm for the CBESD, 3.8 mm for the CCD. In 90% of all set-up for treatment, errors were less than 1 cm. The variation of the CLD was the largest set-up error. This parameter is clinically the most significant. Future treatment delivery should be improved by introducing patient positioning devices such as thermoplastic shells. The electronic portal imaging device (EPID) appears to be an adequate tool to study the accuracy of treatment set-ups like this.
DOI:10.1259/bjr.72.859.10624326
出版商:The British Institute of Radiology
年代:1999
数据来源: WILEY
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