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Biomedical subjects

E Salvini

Publications and source records attributed to E Salvini.

At least 19 recordsLinked to original sources
PubMed1996

[The evaluation of the physical characteristics of a volumetric computer tomograph].

Spiral or volumetric computed tomography (CT) is a new scanning technique which allows the scanning of body regions with a continuously rotating system based on the slip ring technology; the patient is also moved continuously, synchronously with data acquisition. The physical characteristics of spiral CT image acquisition were compared with those of conventional CT images. The modulation transfer function (MTF) has the same values for medium-resolution filters, but lower values for spiral CT for high-resolution and frequency-enhancement filters. The slice sensitivity profile (SSP) describes the longitudinal image resolution for multiplanar reconstructions and was measured in terms of FWHM of the SSP curve. We obtained, for 10-mm slice thickness, a FWHM = 10.4 mm (conventional CT), versus 10.7 mm (Spiral CT), while, for 5-mm slice thickness, the corresponding values were 5.2 mm (conventional CT) and 5.5 mm (spiral CT). Noise was evaluated simply by measuring the standard deviation of the CT numbers, in a region of interest, of a uniform image and with the power spectrum or Wiener spectrum of the same image. To assess overall image quality and yield, the noise equivalent quanta (NEQ) value was also calculated. The values were a little lower for the spiral technique, particularly with high-resolution and enhancement or convolution filters. Dosimetric evaluation of the computed tomography dose index (CTDI) and of the multiple scan average dose (MSAD) was done using an acquisition protocol for average lung dose, in an anthropomorphic phantom and with TL dosimeters. The MSAD was 6.17 +/- 0.20 cGy for conventional CT and 5.98 +/- 0.23 cGy for Spiral CT, while lung dose was 3.25 +/- 0.12 cGy and 3.01 +/- 0.16 cGy, respectively.

Artifacts↗
PubMed1994

[Digital storage phosphor radiography. Doses and image quality].

Digital radiography (DR) based on storage phosphor technology is progressively replacing conventional screen-film system radiographic techniques (CR). However, many questions about image quality and dose reduction are still open. Thus, since DR spatial resolution is always lower than that of high quality screen-film images and image noise is conversely higher, for general radiography examinations especially, the signal-to-noise ratio is always lower with DR than with CR at the same dose level. However, the wide dynamic range, the linear response of storage phosphor detectors and the automatic read-out control of the digital system, enable lower DR X-ray imaging efficiency to be overcome, producing a nearly perfect readout of the image data every time an exposure is made. Moreover, post-processing can make the detection of abnormalities easier. This is why in many ROC clinical accuracy studies DR performed equally or better than CR. Good quality DR images, similar to conventional ones at the same dose levels, are therefore achievable in chest, abdomen, bone and soft-tissues examinations. Dose evaluation protocols are strongly needed in DR since overexposures due to technical mistakes may be overlooked; moreover, doses can be adjusted to the peculiar diagnostic need. The S values shown on any hard-copy image can be used to this purpose, even though it must be pointed out that they do not express the actual mean dose to the detector.

Humans↗
PubMed1994

[The detectability of osteoarticular lesions of the extremities on the television monitor].

The diagnostic accuracy of the light-box reading of conventional (film screen) radiographs of the extremities was compared with that of the same set of images displayed on a 1 k x 1 k interactive monitor after laser digitization. 389 alterations (23 nondisplaced fractures, 129 soft-tissue calcifications and 237 articular bone erosions), identified by two experienced radiologists on 66 conventional radiographs, were the reference standard. ROC statistical analysis was performed on 1,556 observations expressed by four readers. The overall diagnostic performance of the two display modalities were substantially equivalent: no statistically significant differences resulted on the whole, but two individual readers performed better with conventional images. No overall nor individual statistically significant difference was reobserved for the subset of articular erosions either. Light-box reading of conventional radiographs allowed a higher number of calcifications in the soft-tissues and of proximal (carpal) abnormalities to be detected. Although our results indicate the overall high fidelity of monitor-displayed laser-digitized images, major improvements in the performance of digital diagnostic workstations are still required before adopting monitors for routine radiologic activity.

Evaluation Studies as Topic↗
PubMed1994

CT and chest radiography in the evaluation of adult respiratory distress syndrome.

CT is seldom employed in adult respiratory distress syndrome (ARDS), mostly due to problems in transporting and monitoring these severely ill patients. We reviewed the findings of 74 ARDS patients who underwent chest CT. Lung opacities were bilateral in almost all patients and dependent in most cases (86%). The opacities were patchy (42%), homogeneous (23%), ground glass (8%) or mixed (27%). Opacities prevailed in basal regions (68%) compared to hilar and apical ones. Air bronchograms were frequently seen in areas of consolidation (89%). In contrast with previous reports, pleural effusion was a frequent finding (50%) that did not worsen prognosis. Often loculated pneumothorax (32%) was mostly anteromedial. Ineffective position of thoracostomy tubes was detected at CT in 13/20 patients. Pulmonary air cysts (30%), always multiple and mostly bilateral, were associated with a higher mortality (55%) than that of the whole study group (35%). Compared to chest radiographs, CT often yielded additional information (66%), with direct influence on patient treatment in 22% of cases.

Adolescent↗
PubMed1991

[Detection of small bone lesions with digital radiography using storage phosphors].

To date, the skeletal imaging capabilities of digital radiography with storage phosphors have been poorly investigated, and the diagnostic accuracy of this technique has not been thoroughly assessed. To evaluate the performance of storage phosphor digital radiography we compared 66 conventional and 66 digital radiographs of small abnormalities of the extremities (fractures, erosions, calcifications). Conventional images were obtained with a low-speed screen-film system while digital ones were acquired with high-resolution (5 lp/mm max) phosphors and laser-printed on a 8" x 10" film. Two experienced radiologists defined the gold standard (389 abnormalities) and four radiologists scored the findings (1,556 observations) on a five-point discrete scale. ROC analysis indicated film and storage radiography to be equally effective in the overall detection of abnormalities. No difference was found in the individual performances of the four readers, in the site subclasses (wrist, hand), and in the specific detection of fractures and erosions. Digital radiography proved to be superior to conventional radiography in the detection of calcifications in all sites and particularly in the wrist (p less than 0.05). Storage phosphor radiography may replace conventional radiography of the extremities without causing any significant decrease in diagnostic accuracy.

Bone Diseases↗
PubMed1989

A radiologic study by CT scan of pineal size in cancer patients: correlation to melatonin blood levels.

Alterations in size of the pineal body and melatonin secretion have been observed in cancer patients. The present study was carried out to evaluate pineal dimensions in a group of cancer patients and their relation to melatonin blood levels. The study included 70 oncologic patients. As controls, 41 patients with acute or chronic disease other than cancer entered the study. Melatonin serum levels were measured by radioimmunoassay on venous blood samples collected at 9:00 a.m. Pineal size was determined by brain CT scan, by considering the product of the two longest perpendicular diameters, multiplied by the thickness of the stratum. The volume of the pineal body was found to be enlarged in 12/70 (17%) cancer patients, and its mean value was significantly higher than that observed in controls. Melatonin levels were also significantly higher in oncologic patients than in controls. However, there was no correlation between melatonin levels and pineal size in cancer patients. Finally, cancer patients did not show a higher degree of pineal calcifications than controls. The clinical significance of pineal enlargement in cancer patients remains to be understood.

Adult↗
PubMed1989

[Digital radiography with phosphorus memory: verification of the centering of the patient in high-energy radiotherapy].

A digital radiographic system using storage phosphor detectors was employed in order to verify radiotherapy treatments with high energy photon beams (60Co-18 MV X-rays). The wide range linearity of the detectors and also the possibility of digital image post-processing allowed portal films to be obtained with sufficient contrast in all treatment techniques, particularly in the case of mantle fields. The use of digital radiography may become an easy and valuable procedure for therapy verification.

Algorithms↗
PubMed1988

[Digital radiography using light-emitting detectors. Operative principles and characteristics of images].

This paper briefly describes the technical features of a digital radiographic system based on the principle of scanning laser stimulated luminescence. Such aspects as the physics of the stimulable phosphor detector are dealt with, and image acquisition, processing, and hard-copy output. Automatic analysis of pixel histograms is described, in a qualitative way, together with contrast modifications and spatial filtering. Physical image characteristics are reported. The overall performance of digital radiography is examined, together with the current requirements and its eventual developments.

Humans↗
PubMed1987

[Digital radiography with photo-emitting detectors. Technical note].

A specification on a digital radiography system which has been recently installed, based on the principle of scanning laser stimulated luminescence, is explained in short. We have just verified the possibility, among the many potential advantages, to produce good images at the lowest doses and insensitive to over and under exposure.

Evaluation Studies as Topic↗
PubMed1982

[Chondropathy of the patella. Clinico-radiologic study].

Totally 165 cases of chondromalacia patellae, taken from a series of 240 patients, are presented. The cause of the chondromalacia lies in imbalances, displacements, dysplasias of patellae and in femoro-tibial axial deviations. Overload is the constant intermediary between the different starting causes and the same final result. The precocity of the clinical-radiological diagnosis is essential for the timely carrying out of a corrective surgery, directed to remove the starting causes before the reversible chondromalacia develops into irreversible arthrosis.

Cartilage Diseases↗