Dual-energy CT angiography for evaluation of internal carotid artery stenosis and occlusion / 中国医学科学院学报

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSION</b>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.</p>

Thoracic high resolution CT findings of 100 SARS patients in convalescent period / 中国医学科学院学报

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSIONS</b>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.</p>

Coronary artery imaging with 64-slice spiral CT:an initial study / 中华放射学杂志

Objective To evaluate the image quality of coronary CT angiography (CTA) and the diagnostic accuracy for the assessment of coronary artery stenosis with a 64-slice CT scanner.Methods 120 patients with suspected coronary artery disease were studied by ECG-gated 64-slice spiral CT (120 kV, 850 mAs,0.33 s-rotation time,0.6 mm collimation);60 of them also underwent conventional coronary angiography(CCA).Patients with heart rates above 70 bpm received oral?-blockade before the scan. Enhanced scan was performed with an intravenous injection of 60-70 ml contrast agent (370 mg l/ml) and 50 ml saline chaser bolus at 4 ml/s.Images were retrospectively reconstructed under different reformations multiplanar reconstruse-tion(MPR),maximum intensity projection(MIP)and volume rendering technology (VRT)and reviewed by two observers.Image quality was assessed using a 3-point grading scale(excellent, sufficient and non-diagnostic)and the visibility of coronary branches was evaluated.The left main,left anterior descending,left circumflex and right coronary arteries were screened for the presence of over 50% stenosis.Results Sixty-nine percent of the included patients received?-bloekade.The average heart rate was 61?8 bpm and the scan time was 11.9?1.3 s.In the evaluation of image quality with VRT images, 77% patients′images were excellent,18% sufficient,and 5% non-diagnostic.All of the first,most of the second and third,and parts of the fourth subsegment branches could be shown with MPR,MIP and VRT reconstruction images.MPR and MIP displayed better visualization than VRT in showing small branches. Compared with CCA,the sensitivity,specificity,positive and negative predictive value of CTA to identify over 50% stenosis were 93%,98%,87% and 99%,respectively.Conclusion 64-slice spiral CT coronary angiography is a noninvasive and fast method that allows reliable diagnosis of coronary artery stenosis with high image quality.