ABSTRACT
Objective To compare diagnostic accuracy of spiral CT with low dose scanning to normal dose scanning for chronic obstructive pulmonary disease(COPD)and to evaluate clinical application for COPD diagnosis.Methods A total of 120 patients were recruited with a primary diagnosis of COPD,and detailed symptoms and medical history were recorded when patients were hospitalized.These patients were then randomized into two groups and examined with low dose or normal dose CT scanning,respectively.Image quality and effective radiation dose of the two groups were measured and clinical diagnosis of COPD was used as gold standard to assess diagnostic accuracy of low dose scanning for COPD.Results No significant difference on imaging quality was detected between the two groups in our study.However,effective radiation dose in low dose group was only (1.24±0.18)mSv,much lower than that in normal dose group with an effective radiation dose of(3.31±0.52)mSv.The sensitivity of normal dose scan for COPD diagnosis was 87% and the specificity was 57%.Though there was no significant difference between the two groups in diagnostic accuracy,both the sensitivity (92%)and the specificity(80%)of low dose scanning for COPD showed slight inclination.Conclusion Spiral CT with low dose dynamic scanning presented equal diagnostic value,but lower radiation dose for COPD patients,compared to normal dose scanning,which is worth for clinical application.
ABSTRACT
The time-density curves were collected in 106 patients with intracranial tumors.A de- tailed analysis was made among 66 of them whose illness was determined surgically and pathologically.The scanning technique,method of administration of contrast material in dy- namic CT and its value in the qualitative and differential diagnosis of intracranial tumors were discussed.We consider that 1.dynamic CT scan is performed safely and reliably without trauma or pain on patients.2.Due to their various degrees of vascularity and disorders in the blood-brain barrier,different histological kinds of brain tumors have their own typical time-density curves.3.Vascular disorders such as aneurysm,angioma and arteriovenous mal- formation can be determined and differentiated from intracranial tumors or granuloma based on the typical time-density curves.4.Dynamic CT study is of some value in differential diagnosis of various kinds of brain tumors and is important in differentiation between brain tumors and granulomatous lesions.