Digital processing of radiographic images from PACS to publishing

Several studies have addressed the implications of filmless radiologic imaging on telemedicine, diagnostic ability, and electronic teaching files. However, many publishers still require authors to submit hard-copy images for publication of articles and textbooks. This study compares the quality digital images directly exported from picture archive and communications systems (PACS) to images digitized from radiographic film. The authors evaluated the quality of publication-grade glossy photographs produced from digital radiographic images using 3 different methods: (1) film images digitized using a desktop scanner and then printed, (2) digital images obtained directly from PACS then printed, and (3) digital images obtained from PACS and processed to improve sharpness prior to printing. Twenty images were printed using each of the 3 different methods and rated for quality by 7 radiologists. The results were analyzed for statistically significant differences among the image sets. Subjective evaluations of the filmless images found them to be of equal or better quality than the digitized images. Direct electronic transfer of PACS images reduces the number of steps involved in creating publication-quality images as well as providing the means to produce high-quality radiographic images in a digital environment.     

Comparison of radiographic image quality from four digitization devices as viewed on computer monitors

The objective of this study was to compare the quality of radiographic images digitized from commercial-grade and consumer-grade digital cameras and scanners as viewed on computer monitor. Radiographic images were digitized from hardcopy film using a commercial-grade laser scanner, a consumer-grade desktop flatbed scanner, a commercial-grade digital camera, and a consumer-grade digital camera. The quality of images without and with grayscale histogram adjustment was evaluated subjectively by 10 board-certified radiologists. Optical density response was evaluated objectively using a grayscale test pattern. There was no significant difference in subjective quality among images digitized with the commercial scanner, consumer scanner, and commercial camera. The quality of images digitized with the consumer camera was lower than the other 3. Objective tests showed the commercial scanner to have the most linear optical density response. For the purpose of viewing images on a computer monitor, a consumer-grade desktop scanner can produce images of similar quality to those produced by more expensive laser commercial-grade scanners and digital cameras and provides cost-efficient means to digitize radiographic plain films. A consumer-grade camera may not be optimal for use in this setting.     

准分子激光术后超微结构变化与生物组织反应

目的 以超微结构为基础,了解准分子激光表面切削术后角膜生物组织反应特点。方法 透射电镜对38只兔眼4,8,12周角膜组织进行观察和分析,并设对照。结果 角膜基质细胞线粒体和粗面内质网损害;出现功能不良性角膜实质细胞;在各种细胞中有成堆的骶鳞体积聚,提示大量自由基的产生;免疫细胞反应和淋巴细胞的凋亡;气化性碎屑产生;角膜胶原纤维区域性溶解等。结论 准分子激光可使角膜组织产生特异性的生物组织反应,可能是临床合并症的组织病理学基础。     

Platelet von Willebrand factor: an important determinant of the bleeding time in type I von Willebrand's disease

We studied 17 patients with moderate to mild type I von Willebrand's disease (vWd) and correlated the bleeding time with the plasma von Willebrand factor antigen (vWf Ag), the plasma vWf activity (ristocetin cofactor), the platelet vWf Ag, and the platelet vWf activity. We found an excellent correlation between the bleeding time and the platelet vWf activity and, to a lesser extent, between the bleeding time and the platelet vWf Ag. The length of the bleeding time was inversely proportional to the level of the platelet vWf (P less than .001) or, to a lesser extent, the platelet vWf Ag (P less than .05). The plasma vWf Ag and activity did not correlate significantly with the bleeding time. These studies indicate that the platelet vWf is one of the important bleeding time factors in type I vWd and that the platelet vWf plays an important role in the early steps of hemostasis.     

Restoration of thrombolytic potential in plasminogen-deficient mice by bolus administration of plasminogen

Homozygous plasminogen-deficient (Plg-/-) mice had a significantly reduced thrombolytic capacity toward intravenously injected 125I-fibrin labeled plasma clots prepared from Plg-/- murine plasma (9% +/- 3% lysis after 8 hours; (mean +/- SEM, n = 6), as compared with 82% +/- 8% in wild-type mice; P < .0001). Bolus injection of 1 mg purified murine plasminogen in 10- to 17-week-old Plg-/- mice increased the plasminogen antigen and activity levels at 8 hours to normal levels (130 +/- 5 micrograms/mL). Plasminogen administration was associated with significant restoration of thrombolytic potential (64% +/- 7% spontaneous clot lysis; P < .0001 versus lysis without plasminogen injection). Bolus injection of 1 mg plasminogen in homozygous tissue- type plasminogen activator-deficient (t-PA-/-) mice doubled the plasminogen antigen and activity levels after 8 hours and increased 125I-fibrin clot lysis at 8 hours from 13% +/- 3% to 34% +/- 5% (P = .008). Fibrinogen, t-PA antigen and alpha 2-antiplasmin activity levels after 8 hours were not significantly different in the groups with or without plasminogen injection. Injection of plasminogen induced a variable increase (on average 7- to 10-fold) of PAI-1, but no correlation with the extent of spontaneous clot lysis was observed. Histopathologic examination at the end of the experiments revealed that fibrin deposition in the liver of Plg-/- mice was slightly reduced 8 hours after bolus plasminogen injection (P = .007) and markedly reduced after 24 hours (P < .0001). Plasminogen antigen levels in liver extracts were comparable with those found in wild-type mice at 8 hours (130 +/- 20 versus 110 +/- 15 ng/mg protein) and decreased to 25 +/- 3.2 ng/mg protein at 24 hours. Thus, restoration of normal plasminogen levels in Plg-/- mice normalized the thrombolytic potential toward experimentally induced pulmonary emboli, and resulted in removal of endogenous fibrin deposits within 24 hours.