The presence of a color signal close to calcifications should be interpreted with caution, and a flow spectrum should always be recorded to eliminate the twinkling artifact.

Recurrent acute chest syndrome (ACS) has been suggested as a risk factor for chronic lung dysfunction in sickle cell disease. To investigate this hypothesis, lung function tests were performed in 49 sickle cell disease outpatients whose condition was stable, including 23 patients with a history of two to four episodes of ACS (ACS+) and 26 with no history of ACS (ACS-). The two groups were comparable regarding the sex ratio, body mass index, smoking history, physical characteristics, clinical history and usual lung function tests. Respiratory resistance (Rrs), measured using the forced oscillation technique, increased with the number of ACS episodes (r=0.55, p<0.0001) and a significant relationship was observed between Rrs as an independent variable and the expiratory flow rates at 25, 50 and 25-75% of the forced vital capacity as explanatory variables (r= 0.36, p<0.02; r=0.35, p<0.02; and r=0.4, p<0.006, respectively), with higher Rrs being associated with lower expiratory flow rates. The transfer factor (TL,CO) and transfer coefficient (KCO) for CO were significantly higher in the ACS+ group than in the ACS-group (TL,CO=84+/-4 versus 71+/-3%, p<0.004 and KCO=102+/-5 versus 90+/-3%, p<0.05, respectively). The data demonstrate that obstructive lung dysfunction is fairly common in sickle cell disease and suggest that recurrent acute chest syndrome may contribute specific obstructive defects. The increase in respiratory resistance associated with acute chest syndrome was accompanied by an increase in diffusion capacity, suggesting that it may have been related to an increase in lung blood volume.

A retrospective, multi-institutional study was carried out on a series of 50 histologically proved benign hepatic tumors. The 27 hepatic adenomas (HAs) and 23 cases of focal nodular hyperplasia (FNH) were studied with ultrasonography (US) and dynamic computed tomography (CT). Angiography was performed in 26 cases (15 HAs, 11 FNHs); scintigraphy was not used because of its cost. US scans proved nonspecific. CT scans demonstrated hemorrhage in five HAs and were useful in characterizing tumoral vascularity and any intratumoral features such as necrosis or central fibrous scar. The presence of arterial vessels (five patients) in the projection of this central fibrous scar is suggestive of FNH. Dynamic CT scans did not show the type of tumor in most cases. In cases with lesions greater than 3 cm for which doubt as to the diagnosis persists, combined use of morphologic data, scintigraphy, dynamic CT scanning, and angiography can guide the therapeutic decision: surgery or follow-up CT study after use of oral contraceptives is stopped.

Forty hepatic abscesses were examined with dynamic computed tomography (CT). A "double target sign," consisting of a hypodense central area surrounded by first a hyperdense ring and then a hypodense zone, seems to be highly suggestive of abscess formation. In 12 cases, the hepatic parenchyma surrounding the lesion demonstrated transient hyperdensity after contrast injection, possibly due to localized hepatic venous obstruction secondary to acute hepatic inflammation. This is similar to the appearance of an arterioportal fistula.

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