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Conventional and digital mammographic images obtained with storage phosphors were compared. The digital images were acquired with high-resolution 3rd-generation (HR III) screens and specifically adapted algorithms. The experience was made both on a phantom and in vivo. The phantom study was carried out by comparing conventional with digital radiographs acquired with: a) same kV (28) and same mAs; b) same kV (24) and same mAs; c) 28 kV with 30% mAs reduction, in digital images only. The results obtained upon counting the amount of recognizable details per image demonstrated slight loss of information in digital radiographs only when mAs was reduced by 30%. Two hundred patients were studied; they were divided into four groups according to the type of breast (medium inherent contrast or solid breast) and to exposure factors. After conventional mammography, an additional digital radiograph was performed using one of the three techniques previously employed on the phantom. Separately, 10 ductogalactographies and 10 magnification radiographs of microcalcifications were compared; the same exposure factors were used in these images too. The radiographs were viewed by three expert mammographic radiologists; contrast quality and spatial resolution were investigated and a score was given to each image on a 3-grade scale (insufficient, sufficient, good). The comparison of the mean values obtained showed higher contrast and better enhancement of nodular lesions on digital images, on which, however, the depiction of microcalcifications was worse than on conventional radiographs, especially with lower radiation doses, even though the number of detected microcalcifications was the same.

CT features are described and accuracy of the method is discussed in the diagnosis of malignant pleural mesothelioma. Ninety-eight patients suffering from pleural disease mimicking mesothelioma were examined by means of III-generation CT scanners; according to the final diagnosis, 37 patients suffered from malignant pleural mesothelioma, 27 from other malignant pleural diseases and 34 from various benign diseases. In all patients a series of CT signs was evaluated: pleural thickening patterns, lesion spread and possible associated characters. In the diagnosis of mesothelioma CT showed 72.5% sensitivity, 63.8% specificity, 68.3% diagnostic accuracy, 68.5% positive predictive value and 68.2% negative predictive value. Some significant CT patterns in distinguishing malignant from benign pleural disease were identified, while the characterization of malignant disease (mesothelioma versus other neoplastic conditions) proved to be unreliable.

A computed radiography system with solid state detectors (FCR 101) was employed to evaluate the quality of digital images, with optimal and progressively lowered doses, in the study of the chest. Routine chest radiographs of in patients with no pathologic conditions of the chest were studied. The patients were divided into 3 groups: each patient in group A underwent two radiographs, one at 100% and the other at 50% exposure; patients in group B were imaged with 100% and 25% doses, and those in group C received 50% and 25% exposure. Several parameters were employed for image evaluation, and a value was given to each of them (1 = good, 2 = sufficient, 3 = insufficient). Upon comparison of the average values obtained, we observed that the digital technique allowed a most accurate and well-defined representation of the examined parameters at 100% exposure dose and that a 50% reduction did not decrease the informative content in the least. A 25% reduction, however, determined a high degree of background noise and a subsequent, though slight, loss of information.

A solid state digital system (FCR 101) was employed in our comparative evaluation of the image quality of conventional versus digital techniques in the study of colon by means of double-contrast enema. Sixty patients were examined with a single AP view, using digital radiography with 100% radiation dose and progressive 50% and 75% reductions; the radiographs thus obtained were then compared with the corresponding conventional ones. The examined parameters were organ profile and mucosal pattern. Each digital and conventional radiograph was evaluated by 2 independent radiologists and a value was given to each parameter i.e., 1 = good, 2 = sufficient, 3 = insufficient. Upon comparison of the average values obtained for digital and conventional radiographs in optimal conditions and with a dose reduced by 50%, the digital technique was seen to give a more detailed and accurate representation of both low-contrast mucosal pattern and of organ profile. With the dose reduced by 75%, a slight increase was observed in background noise which caused a slight loss in image definition, but this did not reduce image readability with respect to conventional radiographs. To conclude, the digital method with a 50% exposure reduction is to be preferred in the examination of the colon, especially in pediatric radiology; furthermore, since this technique allows better detailing at lower contrast, it is to be preferred in the study of the pathologic conditions affecting mainly/only the mucosal pattern--e.g., cancer, ulcerative colitis, Crohn's disease, and so on. An exposure dose reduced by 75% may be used for following lesions previously diagnosed and when a less detailed depiction of the mucosal pattern is enough.

Pseudomyxoma peritonei is an uncommon disorder, usually the sequelae of mucocele or mucinous adenocarcinoma of the appendix or mucinous cistoadenocarcinoma of the ovary. Two cases of pseudomyxoma peritonei were examined by ultrasound and one case by CT. US revealed, in a case, multiple echogenic small masses scattering on the peritoneal surface or floating in ascites. CT showed, in the second case, a huge mass consisting of a low attenuation material with internal septation. Also a perforation of intestinal loops in the mass was demonstrated. CT and US appearance of pseudomyxoma peritonei in our experience and in previously reported cases are discussed.