Optimisation of radiological protocols for chest imaging using computed radiography and flat-panel X-ray detectors.

PURPOSE: Digital radiography technology has replaced conventional screen-film systems in many hospitals. Despite the different characteristics of new detector materials, frequently, the same radiological protocols previously optimised for screen film are still used with digital equipment without any critical review. This study addressed optimisation of exposure settings for chest examinations with digital systems, considering both image quality and patient dose. MATERIALS AND METHODS: Images acquired with direct digital radiography equipment and a computed radiography system were analysed with specially developed commercial software with a four-alternative forced-choice method: the most promising protocols were then scored by two senior radiologists. RESULTS: Digital technology offers a wide dynamic range and the ability to postprocess images, allowing use of lower tube potentials in chest examinations. The computed radiography system showed both better image quality and lower dose at lower energies (85 kVp and 95 kVp) than those currently used (125 kVp). Direct digital radiography equipment confirmed both its superior image quality and lower dose requirements compared with the storage phosphor plate system. CONCLUSIONS: Generally, lowering tube potentials in chest examinations seems to allow better image quality/effective dose ratio when using digital equipment.

Contrast-enhanced US of the prostate with time/intensity curves: Preliminary results.

PURPOSE: To evaluate the diagnostic performance of ultrasonography using second-generation contrast agent in the study of patients with focal prostate lesions and increased serum prostate-specific antigen (PSA) level. MATERIALS AND METHODS: SIX CONSECUTIVE PATIENTS (AGE RANGE: 72-87 years) with increased PSA (≥4 ng/ml) underwent transrectal ultrasonography (TRUS) followed by contrast-enhanced ultrasonography (CEUS) with injection of second-generation contrast agent. All patients showed areas of abnormal echostructure suspicious for neoplastic lesions. On the basis of CEUS, a time/intensity curve of the suspected area was compared to that of a normal-appearing distant area of the gland and to the results of biopsy of the hypoechoic area. RESULTS: AT CEUS TWO DIFFERENT PATTERNS OF ENHANCEMENT WERE IDENTIFIED AND CONSIDERED TO BE SIGNIFICANT: pattern 1 characterized by a rapid rise in the time/intensity curve of the suspected area compared with the normal gland. Two out of six patients had this pattern and biopsy showed cancer in the biopsied area. Pattern 2 was characterized by a similar rise in the time/intensity curve of the suspected area compared with the normal gland. Four out of six patients had this pattern and biopsy showed prostatitis in the biopsied area. CONCLUSIONS: CEUS using second-generation contrast agent can on the basis of time/intensity curves show differences in vascularization in normal and pathological tissue. Evaluation of the two patterns seems to be useful for identifying areas requiring biopsy, particularly when peripheral hypoechoic areas are observed at TRUS. Our data need to be confirmed in a larger patient population.

[The use of a questionnaire to test the reliability of protocols for the indication of radiologic tests in emergencies]. / Impiego di un questionario a verifica dell'affidabilità dei protocolli di indicazione agli esami radiologici nelle urgenze.

The authors developed a series of protocols for selecting patients who need emergency radiography, based on clinical criteria that maximize the yield of abnormal radiographs. In order to test safety and reliability of the protocols and to define the reasons for requesting emergency radiographs, a prospective analysis was carried out, by means of a questionnaire, on 1000 consecutive patients referred to our Accident and Emergency Department for radiography. Seven hundred and twenty-nine patients were considered as negative according to protocol criteria: none of them was found positive on X-ray examination. Of them, 639 exams were requested for medico-legal reasons and 90 for patient reassuring. Of 271 patients considered as true positive or probably positive according to the screening criteria, all the true positive cases were such also on X-ray examinations, whereas, among the probably positives, only 31 were confirmed as positive on radiological studies. Our results demonstrate the efficacy of the suggested protocols: had these referral criteria been used for the patients in our study, only 271 examinations would have been performed with no radiographic abnormalities missed. In addition, this grid included 94 cases evaluated as "probably" positive which were subsequently found negative at X-rays, which makes a further safety margin. Our analysis also shows the low therapeutic value of emergency radiographs in both nasal bone injury and post-traumatic oblique rib views. Therefore we suggest selecting patients who need X-rays based on the clinical criteria shown in our protocols: this could result in economic saving and decreased radiation exposure, with no risks of clinical underestimation of the pattern.