[Dual-energy CT angiography for evaluation of internal carotid artery stenosis and occlusion].

OBJECTIVE: To compare the feasibility of bone and calcified plaque subtracted dual-energy CT angiography (CTA) with time of flight magnetic resonance angiography (TOF MRA) in evaluation of internal carotid artery atherosclerosis. METHODS: Totally 32 patients received a dual-energy CTA scan, along with a cerebral TOF MRA scan before or after CTA examination from one day to one month. Dual-energy software was used for bone and calcified plaque subtraction. Five anatomical segments were described for each internal carotid artery according to Fischer (1938). Ratings were based on a 1-4 scale for the dual-energy CTA maximum intensity projection (MIP) image: 1 not diagnostic, 2 partially diagnostic, 3 diagnostic, and 4 excellent. Lesions were categorized as mild (0-29%), moderate (30%-69%), severe (70%-99%), or occluded (no flow detected). Stenosis of internal carotid artery was evaluated based on post-subtracted CTA images and TOF MRA images. RESULTS: In 320 arterial segments, 99% of arterial segments were > or = 3 score. Grading of stenosis on dual-energy CTA agreed with grading of stenoses on MRA images in 98% of arteries. In the mild and occlusion group, the agreement was 100% respectively. In the moderate and severe group, dual-energy CTA showed more severe stenosis than MRA in 7 vessels and there was significant difference between the results from the two different modalities (Z = -3.071, P = 0.002). CONCLUSION: Dual-energy CTA can be used to assess the stenosis of internal arteries around skull base, but may exaggerate the severe stenosis of cerebral arteries compared with TOF MRA.

[Thoracic high resolution CT findings of 100 SARS patients in convalescent period].

OBJECTIVE: To study thoracic high resolution CT findings of severe acute respiratory syndrome (SARS) patients in convalescent period and the relationship between the features with laboratory and pulmonary function results. METHODS: All the 100 SARS patients who had been discharged from hospital for about 2 months underwent thoracic high resolution CT examinations. Among them, 65 also had laboratory results and 91 underwent examinations of pulmonary function. RESULTS: Forty-nine SARS patients (49.0%, 49/100) in convalescent period still had abnormal findings in CT examination. And ground-glass opacification (95.9%, 47/49) and reticular opacification (59.2%, 29/49) were common. There was no significant difference in the level of lymphocytes and CD4 cells among groups divided according to severity of CT findings (P > 0.01). Diffusing capacity for carbon monoxide (DLco%) of level 2 and 3 were statistically lower than that of level 0 (P < 0.01). CONCLUSIONS: The features of CT findings of SARS patients in convalescent period are not the same as those of patients in period of apparent manifestation. The high resolution CT can reflect pulmonary diffusing function to some degree.