[A comparison between an ionic paramagnetic contrast agent (Gd-DTPA) and a nonionic one (Gd-DTPA-BMA) in functional kidney evaluation with magnetic resonance]. / Confronto tra un mezzo di contrasto paramagnetico ionico (Gd-DTPA) e uno non ionico (Gd-DTPA-BMA) nella valutazione funzionale del rene con Risonanza Magnetica.

INTRODUCTION: The combination of TGE sequences with bolus injection of paramagnetic contrast agents permits to study renal function and perfusion. We studied renal function with both an ionic (Gd-DTPA) and a nonionic paramagnetic contrast agent (Gd-DTPA-BMA) to compare their kinetics in normal kidneys. MATERIAL AND METHODS: Twenty MR examinations were performed on 20 subjects with normal renal function. Ten subjects were examined after i.v. injection of Gd-DTPA and the other ten subjects after i.v. injection of Gd-DTPA-BMA. MR examinations were performed on a Philips ACS II unit (1.5 T). Two sequences were acquired in all cases; an SE coronal T1-weighted sequence (TR/TE = 600/19 ms) and a TGE coronal T1-weighted sequence (TR/TE = 12/5 ms, flip angle = 25 degrees) performed after bolus injection of the contrast agent at 0.1 mmol/kg. Signal intensity time curves were obtained in all the cases. The signal intensity of the cortex, corticomedullary junction, medulla and the pyelocaliceal system of each kidney was measured using a region of interest (ROI). Signal intensity curves were analyzed considering some quantitative parameters such as the area under the curve (AUC), the peak (P) and the time to peak (T-P). RESULTS: In the subjects with normal renal function, four phases were demonstrated after the i.v. injection of either Gd-DTPA or Gd-DTPA-BMA, namely the cortical phase, the cortico-medullary junction phase, the medullary phase and the pyelocaliceal system phase. No statistically significant differences between the two agents were demonstrated in signal intensity time curves and quantitative parameters. CONCLUSIONS: Gd-DTPA and Gd-DTPA-BMA showed the same efficacy in renal function studies.

Cystic fibrosis in children: HRCT findings and distribution of disease.

To assess the type, severity, and regional lung distribution of cystic fibrosis (CF) lesions as shown using high-resolution CT (HRCT), comparing these findings with chest radiographs and pulmonary function tests (PFTs), we obtained HRCTs in 36 patients with CF (mean age 13), who were clinically stable. We assessed four lung regions (upper and lower, right and left) and assigned each a semiquantitative score for (a) bronchial abnormalities, (b) parenchymal abnormalities, and (c) overinflation, based on the severity and profusion of the corresponding lesions. A similar regional assessment of chest radiographs was also done using the Chrispin-Norman method. PFT results were correlated with the radiological data. On HRCT, bronchial lesions were present in 89% of the patients and in 78% of the regions; bronchiectasis was the predominant abnormality in our population, visible in 100% of the abnormal regions. Less frequent were bronchial wall thickening (48%) and mucous plugs (29%). Parenchymal abnormalities were recognizable in 58% of the patients and 31% of the regions; alveolar consolidation was more frequent (80%) than were destructive changes (36%). Overinflation was found in 81% of the patients and 85% of the regions. We found the severity and profusion of bronchial lesions and parenchymal destructive changes to be unevenly distributed among the different regions, the upper lungs being more heavily involved than the lower, particularly on the right. Alveolar consolidation and overinflation were more uniform in distribution. HRCT patient scores correlated significantly with radiographic scores (r = 0.861) and with PFTs, especially with forced expiratory volume for 1 s (FEV1; r = 0.658). HRCT can be useful in the clinical management of patients with CF, depicting the type and distribution of bronchial and parenchymal lesions, particularly when chest radiographic results are unclear. In the planning and postural drainage, special attention should be given to the apical and posterior parts of the lungs, especially on the right; these are the areas most frequently and most severely involved by the disease.