ABSTRACT
Magnetic resonance first-pass (MRFP) imaging awaits longitudinal clinical trials for quantification of myocardial perfusion. The purpose of this study was to assess inter- and intraobserver agreement of this method. Seventeen MRFP studies (14 rest and 3 under adenosine-induced hyperemia) from 14 patients were acquired. Two observers visually graded study quality. Each study was subdivided into eight regions. Both observers analyzed all 17 studies (8 x 17 = 136 regions) for interobserver agreement. Each observer then analyzed 10 of the 17 studies a second time (2 x 8 x 10 = 160 regions) for intraobserver agreement. Signal intensity curves were obtained with Argus software (Siemens, Iselin, NJ). The maximum amplitude of the impulse response function (Rmax) and the change of signal intensity (deltaSImax) of the contrast bolus were determined. Intraclass correlation coefficient was used to determine intra- and interobserver agreement. The quality was good or excellent in 14 studies. Intraobserver agreement of Rmax and deltaSImax were good (0.85 and 0.80, n = 160). Interobserver agreement of Rmax was fair (0.55, n = 136) but improved after exclusion of poor-quality studies (0.88, n = 112). Interobserver agreement of deltaSImax was good (0.73) and improved less than Rmax with study quality (0.83). Interobserver agreement for Rmax in individual myocardial regions before and after exclusion of studies with poor quality changed most markedly in lateral and posterior regions (0.69 and 0.65 vs. 0.97 and 0.94), where signal-to-noise ratios were reduced compared with anteroseptal regions (p < 0.01). Analysis of MRFP images provides good intraobserver agreement. Interobserver agreement of the quantitative perfusion analysis is good under the premise of good image quality.
Subject(s)
Coronary Disease/diagnosis , Magnetic Resonance Imaging/methods , Observer Variation , Adult , Aged , Analysis of Variance , Coronary Circulation , Female , Humans , Hyperemia/chemically induced , Image Processing, Computer-Assisted , Male , Middle Aged , Random AllocationSubject(s)
Contrast Media/pharmacokinetics , Coronary Disease/diagnosis , Gadolinium DTPA/pharmacokinetics , Magnetic Resonance Imaging , Blood Flow Velocity/drug effects , Contrast Media/administration & dosage , Coronary Circulation/drug effects , Coronary Disease/metabolism , Coronary Disease/physiopathology , Gadolinium DTPA/administration & dosage , Humans , Injections, IntravenousABSTRACT
Clinical studies suggest that magnetic resonance first-pass (MRFP) perfusion imaging is comparable to current diagnostic tests that are used clinically for the assessment of myocardial perfusion. In addition, magnetic resonance imaging (MRI) perfusion imaging is a noninvasive method for determining myocardial blood flow. The spatial resolution (in-plane spatial resolution < 3 mm) is sufficient to differentiate between subendocardial perfusion and subepicardial perfusion. The measurement can be repeated regularly without any adverse effects for the patient. MRI perfusion measurements can be combined with the evaluation of global function and regional wall thickening. Currently, there is no other imaging technique that offers similar advantages. The MRI perfusion measurements can be carried out during baseline conditions and during maximal hyperemia induced with either adenosine or dipyridamole. The ratio of the measured myocardial blood flows provides an estimate of the absolute and relative myocardial perfusion reserve. The perfusion reserve determined with MRFP imaging is a quantitative measure for the assessment of the collateral-dependent myocardial flow. Based on the available data using MRFP perfusion imaging, the current clinical first-line perfusion imaging tests are going to be challenged in the near future. J. Magn. Reson. Imaging 1999;10:676-685.
