OBJECTIVE: To evaluate the reproducibility of unenhanced and contrast-enhanced computed tomography in the assessment of patients with acute pancreatitis. MATERIALS AND METHODS: Fifty-one unenhanced and contrast-enhanced abdominal computed tomography studies of patients with acute pancreatitis were blindly reviewed by two radiologists (observers 1 and 2). The morphological index was separately calculated for unenhanced and contrast-enhanced computed tomography and the disease severity index was established. Intraobserver and interobserver reproducibility of computed tomography was measured by means of the kappa index (kappa). RESULTS: Interobserver agreement was kappa = 0.666, 0.705, 0.648, 0.547 and 0.631, respectively for unenhanced and contrast-enhanced morphological index, presence of pancreatic necrosis, pancreatic necrosis extension, and disease severity index. Intraobserver agreement (observers 1 and 2, respectively) was kappa = 0.796 and 0.732 for unenhanced morphological index; kappa = 0.725 and 0.802 for contrast-enhanced morphological index; kappa = 0.674 and 0.849 for presence of pancreatic necrosis; kappa = 0.606 and 0.770 for pancreatic necrosis extension; and kappa = 0.801 and 0.687 for disease severity index at computed tomography. CONCLUSION: Computed tomography for determination of morphological index and disease severity index in the staging of acute pancreatitis is a quite reproducible method. The absence of contrast-enhancement does not affect the computed tomography morphological index reproducibility.

Keywords: Pancreatitis, X-ray computed tomography, Disease severity index, Prognosis, Contrast media, Necrosis

OBJECTIVE: To evaluate the interobserver agreement on non-contrast computed tomography interpretation by a group of experienced abdominal radiologists, for the study of urolithiasis in patients presenting acute flank pain. MATERIALS AND METHODS: Prospective study of 52 patients submitted to non-contrast enhanced helical computed tomography. The images were subsequently analyzed by three independent observers, with the interobserver agreement assessed by means of the kappa (kappa) statistical method. The following parameters were analyzed: a) presence, localization and measurement of ureteral calculi; b) intrarenal calyceal system dilatation; c) perirenal fat heterogeneity; d) ureteral dilatation; e) ureteral wall edema (halo sign). RESULTS: Ureteral calculi were found in 40 of 52 patients (77%). The interobserver agreement was almost perfect as regards identification of ureteral calculi (kappa = 0.89) and ureteral dilatation (kappa = 0.87), substantial for calyceal system dilatation (kappa = 0.77), and moderate for perirenal fat heterogeneity (kappa = 0.55) and ureteral wall edema (kappa = 0.56). CONCLUSION: Non-contrast-enhanced abdominal computed tomography presents high reproducibility in the evaluation of urolithiasis and secondary signs of the calyceal system obstruction.

Keywords: Lithiasis, Ureteral calculi, Flank pain, Computed tomography

New imaging techniques have been developed with the objective of obtaining not only a structural assessment, but also a metabolic and functional analysis of different organs and types of lesions. Among such tools perfusion computed tomography (PCT) has recently aroused the interest of many researchers in studying the applicability of such imaging modality in the evaluation of abdominal organs and diseases. Analysis of the biological behavior of healthy and diseased tissues, differentiation of inflammatory processes from tumors, and diagnosis of tumor recurrence after minimally invasive therapies can be mentioned as applications of such an imaging modality. The main features of PCT are related to its ability to characterize different perfusional behaviors reflecting biological changes of certain lesions and diseased tissues. Thus, the present study was aimed at carrying out a comprehensive literature review, describing the key techniques and protocols utilized in PCT imaging, main clinical applications, advantages and disadvantages of the method, besides proposing an imaging protocol that can be adopted by both private and public health services, with good reproducibility and easy implementation.

Keywords: Perfusion; Computed tomography; Biomarkers; Angiogenesis; Neoplasm; Contrast media.

OBJECTIVE: To assess the reduction of estimated radiation dose in abdominal computed tomography following the implementation of new scan protocols on the basis of clinical suspicion and of adjusted images acquisition parameters. MATERIALS AND METHODS: Retrospective and prospective review of reports on radiation dose from abdominal CT scans performed three months before (group A - 551 studies) and three months after (group B - 788 studies) implementation of new scan protocols proposed as a function of clinical indications. Also, the images acquisition parameters were adjusted to reduce the radiation dose at each scan phase. The groups were compared for mean number of acquisition phases, mean CTDI_vol per phase, mean DLP per phase, and mean DLP per scan. RESULTS: A significant reduction was observed for group B as regards all the analyzed aspects, as follows: 33.9%, 25.0%, 27.0% and 52.5%, respectively for number of acquisition phases, CTDI_vol per phase, DLP per phase and DLP per scan (p < 0.001). CONCLUSION: The rational use of abdominal computed tomography scan phases based on the clinical suspicion in conjunction with the adjusted images acquisition parameters allows for a 50% reduction in the radiation dose from abdominal computed tomography scans.

Keywords: Computed tomography; Abdomen; Contrast media; Radiation dose; Radiation protection.