The impact of Magnetic Resonance Imaging (MRI) on XXXX and incidence: minimal impact within a population-based study.

@entity1 @entity64 @entity63 @entity1188 @entity385
BACKGROUND: There are several situations in which magnetic resonance imaging (MRI) might impact whether an cerebrovascular event is considered a new @entity64 . These include clinically non-focal events with positive imaging for acute @entity385 , and worsening of older symptoms without evidence of new @entity1188 on MRI. We sought to investigate the impact of MRI on @entity64 detection and @entity64 incidence, by describing agreement between a strictly clinical definition of @entity64 and a definition based on physician opinion, including MRI imaging findings. METHODS: All hospitalized @entity64 that occurred in five Ohio and Northern Kentucky counties (population 1.3 million) in the calendar year of 2005 were identified using ICD-9 discharge codes 430-436. The two definitions used were: "clinical case definition" which included sudden onset focal neurologic symptoms referable to a vascular territory for >24  h, compared to the "best clinical judgment of the physician definition", which considers all relevant information, including neuroimaging findings. The 95  % confidence intervals (CI) for the incidence rates were calculated assuming a Poisson distribution. Rates were standardized to the 2000 U.S. population, adjusting for age, race, and sex, and included all age groups. RESULTS: There were 2403 @entity385 events in 2269 @entity1 ; 1556 (64  %) had MRI performed. Of the events, 2049 (83  %) were cases by both definitions, 185 (7.7  %) met the clinical case definition but were non-cases in the physician's opinion and 169 (7.0  %) were non-cases by clinical definition but were cases in the physician's opinion. There was no significant difference in the incidence rates of first-ever or total @entity63 @entity64 generated by the two different definitions, or when only those with MRI imaging were included. CONCLUSIONS: We found that MRI findings do not appear to substantially change @entity64 incidence estimates, as the strictly clinical definition of @entity64 did not significantly differ from a definition that included imaging findings. Including MRI in the case definition "rules out" almost the same number of @entity64 as it "rules in".
